imaqHistogram
Usage
HistogramReport* imaqHistogram(const Image* image, int numClasses, float min, float max, const Image* mask);
Purpose
Calculates the histogram, or pixel distribution, of an image.
Image Types Supported
IMAQ_IMAGE_U8, IMAQ_IMAGE_I16, IMAQ_IMAGE_SGL
Parameters
|
Name
|
Type
|
Description
|
|---|---|---|
| image | const Image* | The image whose histogram the function calculates. |
| numClasses | int | The number of classes into which the function separates the pixels. |
| min | float | The minimum pixel value to consider for the histogram. The function does not count pixels with values less than min. |
| max | float | The maximum pixel value to consider for the histogram. The function does not count pixels with values greater than max. |
| mask | const Image* | An optional mask image. This image must be an IMAQ_IMAGE_U8 image. When calculating the histogram, the function considers only those pixels in image whose corresponding pixels in mask are non-zero. Set this parameter to NULL if you want the function to perform a histogram on the whole image. |
Return Value
| Type |
Description |
|---|---|
| HistogramReport* | On success, this function returns a report describing the pixel value classification. On failure, this function returns NULL. To get extended error information, call imaqGetLastError(). When you are finished with the report, dispose of it by calling imaqDispose(). |
Parameter Discussion
min—Setting both min and max to 0 causes the function to set min to 0 for 8-bit images and to the actual minimum value of the image for all other image types.
max—Setting both min and max to 0 causes the function to set max to 255 for 8-bit images and to the actual maximum value of the image for all other image types.